Electromagnetic switch matrix



April 15, 1969 suo KUDO ETAL 3,439,301

ELECTROMAGNETIC SWITCH MATRIX Sheet Filed Jan. 26. 1967 April 15., 1969 TETSUO KUDO ETAL 3,439,301

ELECTROMAGNETIC SWITCH MATRIX Filed Jan- 26. 1967 Sheet 2 of s April 15, 1969 TETSUO KUDO ETAI- 3,439,301

ELECTROMAGNETIC SWITCH MATRIX Filed Jan. 26. 1967 Sheet 5 April 15, 1969 TETSUO KUDO ET AL 3,439,301

v ELECTROMAGNETIC SWITCH MATRIX Filed Jan. 26. 1967 Sheet 4 of e April 15, 1969 TETSUO KU'DO ET AL 3,439,301

ELECTROMAGNETIC SWITCH MATRIX Sheet Filed Jan. 26. 1967 FIG. 8

IIIIII II. I

April 15, 1969 TETSUO KUDQ ET AL 3,439,301

' ELECTROMAGNETIC SWITCH MATRIX Filed Jan. 26. 1967 Sheet 6 of a FIG.

1 9/0"? ART FIG. /2

United States Patent Int. (:1. H01h67/14, 1/66 U.S. Cl. 335112 13 Claims ABSTRACT OF THE DISCLOSURE An electromagnetic switch matrix comprises a magnetic shunt plate and a plurality of electromagnetic switches. Each of the electromagnetic switches comprises a rod-like core of magnetic material extending through and positioned in the shunt plate perpendicularly to the shunt plate and for a substantially equal length on each side of the shunt plate. The electromagnetic switches are positioned in the shunt plate in spaced relation to each other in columns and rows in a manner whereby the common planes of the switches of one of a row and column of the switches are parallel to each other and are substantially perpendicular to the common planes of the switches of the next adjacent one of a row and column of the switches and the electromagnetic switches of the other of a row and column of the switches are perpendicular to each other and at an angle of 45 with the other of the row and column.

The present invention relates to an electromagnetic switch matrix.

An electromagnetic switch is described in the Bell Telephone Laboratories Record of February 1964, p. 71 to 75. The electromagnetic switch may be utilized in a matrix arrangement and is known as a Ferreed. The known electromagnetic switch has several disadvantages, among which are its magnetic path, which is not particularly closed so that the magnetic reluctance is large, its low efiiciency, its large dimensions and its great weight, which necessitate a considerable magnitude of electrical power to operate said switch and which make the said switch expensive in operation.

The principal object of the present invention is to provide a new and improved electromagnetic switch matrix. The electromagnetic switch matrix of the present invention avoids the disadvantages of the known electromagnetic switch without restricting the continuous winding of the coils of the electromagnetic switches thereof in the process of manufacture. The electromagnetic switch matrix of the present invention has small dimensions and is of light weight, and operates efliciently, effectively and reliably on a smaller magnitude of electrical power than is required for the known electromagnetic switch matrix. The electromagnetic switch matrix of the present invention has a minimum of mutual interference between the switches thereof and operates in a stable manner.

In accordance with the present invention, an electromagnetic switch matrix comprises a magnetic shunt plate and a plurality of electromagnetic switches. Each electromagnetic switch comprises a rod-like core of magnetic material extending through and positioned in the mag netic shunt plate substantially perpendicularly to the magnetic shunt plate and for a substantially equal length on each side of the shunt plate. The core has an axis extending substantially perpendicularly to the shunt plate. Energizing coils are coaxially wound on the core on each side of the shunt plate for providing a magnetic field. Sealed contacts extend through and are positioned in the magnetic shunt plate substantially perpendicularly to the magnetic shunt plate and for a substantially equal length on each side of the shunt plate. The sealed contacts comprise at least a single substantially elongated housing positioned in operative proximity with the core and having an axis extending substantially perpendicularly to the magnetic shunt plate. The axis of the core and the axis of the housing of the sealed contacts form a common plane. The plurality of electromagnetic switches are positioned in the shunt plate in spaced relation to each other in columns and rows in a manner whereby the common planes of the electromagnetic switches of one of a row and column of the switches are parallel to each other and are substantially perpendicular to the common planes of the switches of the next adjacent one of a row and column of the switches.

The sealed contacts of each of the electromagnetic switches preferably comprise a pair of substantially elongated housings positioned in operative proximity with the core on either side thereof and each having an axis extending substantially perpendicularly to the magnetic shunt plate. The axis of the core and the axes of the housings of the sealed cont-acts form a common plane. The housing of the sealed contacts of each of the electromagnetic switches houses a pair of magnetizable reed elements each passing through and extending from an opposite end of the housing, having free ends adjacent each other in the central area of the housing and having outer terminals for connection to electrical conductors. The coils when energized provide a'magnetic field of a determined direction in the central area of the housing and the residual magnetism of the core provides a magnetic field of the same direction in the central area of the housing for magnetizing the free ends of the reed elements of the sealed contact means in a predetermined manner dependent upon the total energization of the coils. The coils of each of the electromagnetic switches comprise an upper inner coil coaxially Wound on the core on one side of the shunt plate, an upper outer coil coaxially wound on the upper inner coil, a lower inner coil coaxially wound on the core on the other side of the shunt plate and a lower outer coil coaxially wound on the lower inner coil. Each of the electromagnetic switches further comprises a magnetic yoke coupled to one end of the core and to the cor-responding ends of the housing of each of the sealed contacts and another magnetic yoke coupled to the other end of the core and to the corresponding ends of the housing of each of the sealed contacts. The common planes of the electromagnetic switches of alternate ones of one of a row and column of the switches are parallel to each other and the common planes of the electromagnetic switches of the alternate others of the one of a row and column of the switches are parallel to each other, and the common planes of the alternate ones of the switches and the common planes of the alternate others of the switches are substantially perpendicular to each other.

In order that the present invention may be readily carried into etfect, it will now be described with reference to the accompanying drawings, wherein:

FIG. 1 is a perspective view, partly cut away, of an embodiment of the electromagnetic switch matrix of the present invention;

FIG. 2 is a perspective view, partly cut away, of an electromagnet of an embodiment of an electromagnetic switch of the electromagnetic switch matrix of FIG. 1;

FIG. 3 is a perspective view, of a part of the electromagnet of FIG. 2;

FIG. 4 is a schematic circuit diagram of the electromagnetic switch matrix of the present invention;

FIG. 5 is a side view, partly in section, of an embodiment of an electromagnetic switch of the electromagnetic switch matrix of FIG. 1;

FIG. 5 is a side view, partly in section, of an embodielectromagnets of the electromagnetic switches of the electromagnetic switch matrix of FIG. 1 in the process of manufacture;

FIGS. 8 and 9 are side views, partly in section, of part-s of an embodiment of an electromagnetic switch of the electromagnetic switch matrix of FIG. 1;

FIG. 10 is a schematic diagram, partly in section, illustrating the windings of the coils of an electromagnetic switch of the electromagnetic switch matrix of the present invention;

FIG. 11 is a schematic diagram of the layout of an electromagnetic switch matrix of the prior art; and

FIG. 12 is a schematic diagram of an embodiment of the layout of the electromagnetic switch matrix of the present invention.

In the figures, the same components are identified by the same reference numerals.

In FIGS. 1, 2 and 3 the electromagnet of the electro magnetic switch of the present invention comprises a core 1 of semi-hard magnetic material of rod-like configuration. A suitable semi-hard magnetic material for the core 1 is Remendur. As shown in FIGS. 1 and 2, an inner upper coil 2 is wound on the core 1 on approximately one half the axial length of said core, and an inner lower coil 2' is wound on said core on approximately the other half the axial length of said core. An outer upper coil 3 is wound on the inner upper coil 2 of the core 1 on approximately more than half the axial length of said inner upper coil, and an outer lower coil 3 is wound on the inner lower coil 2 of said core on approximately more than half the axial length of said inner lower coil.

The inner and outer coils 2 and 2' and 3 and 3' are electrically insulated from the core 1, so that the inner coils 2 and 2' are wound directly on said core when the surface of said core is electrically non-conductive, and when said surface of said core is electrically conductive, electrical insulation (not shown in the figures) is interposed between said core and said inner coils. A vinyl sleeve or wrapping is a suitable electrical insulation between the core 1 and the inner coils 2 and 2.

A pair of scaled magnetically operated contact devices 4 and 4' are spaced from the electromagnet comprising the core 1, the inner windings 2 and 2 and the outer windings 3 and 3' in coplanar relation with said electromagnet on either side thereof. The axes of the contact devices 4 and 4 are coplanar with the axis of the core 1 of the electromagnet (FIGS. 1 and 5). An upper yoke 5 is afiixed at its central portion to the upper end of the core 1, at one end thereof to the upper end of the contact device 4 and at the opposite end thereof to the upper end of the contact device 4'. A lower yoke 5 is aflixed at its central portion to the lower end of the core 1, at one end thereof to the lower end of the contact device 4 and at the opposite end thereof to the lower end of the contact device 4' (FIGS. 1 and 5).

The yokes 5 and 5 comprise magnetic material and function to mechanically support the contact devices 4 and 4' in position relative to the electromagnet 1, 2, 2', 3, 3' and to strengthen the magnetic coupling of said electromagnet with said contact devices. The yokes 5 and 5 magnetically couple the ends of the core 1 to the reed components of the contact devices 4 and 4'.

The contact devices 4 and 4' may be identical. Each of the contact devices 4 and 4' comprises a magnetically operated reed switch. As shown in FIGS. 1, 5, 8 and 9, the reed switch of each of the contact devices 4 and 4 comprises an upper reed element 6a and 6a, respectively, and a lower reed element 6b and 6b, respectively, of magnetic material. The reed elements 6a and 6b of the contact device 4 are sealed respectively in the upper end and the lower end of a tube or other suitable housing 7 of glass or other suitable material filled with an inert or inactive gas or mixture of gases such as, for example, hydrogen, nitrogen and/or the like. The reed elements 6a and 6b of the contact device 4 are sealed respectively in the upper end and the lower end of a tube or other suitable housing 7 of glass or other suitable material filled with an inert or inactive gas or mixture of gases such as, for example, hydrogen, nitrogen and/ or the like.

The upper end of the upper reed element 6a of each contact device 4 of a row of the matrix extends out of the upper end of the housing 7 and is electrically connected to an electrical conductor 8 (FIG. 1). The upper end of the upper reed element 6a of each contact device 4 of the same row of the matrix extends out of the upper end of the housing 7 and is electrically connected to an electrical conductor 8 (FIG. 1). The lower end of the lower reed element 6b of each contact device 4 of a column of the matrix extends out of the lower end of the housing 7 and is electrically connected to an electrical conductor 9 (FIG. 1). The lower end of the lower reed element 6b of each contact device 4 of the same column of the matrix extends out of the lower end of the housing 7 and is electrically connected to an electrical conductor 9' (FIG. 1).

The electrical conductors 8 and 8' are in parallel spaced relation to each other and correspond to the horizontal connections of FIG. 4. The electrical conductors 9 and 9' are .in parallel spaced relation to each other and are at right angles to the conductors 8 and 8 and correspond to the vertical connections of FIG. 4. The connections 8, 8, 9 and 9 form a coplanar grid, as shown in FIG. 4 and may be utilized as voice path elements in a telephone exchange. It is seen (FIG. 1) that electrical contact of the reed elements 6a and 6b closes an electrical circuit between the conductors 8 and 9 and electrical contact of the reed elements 6a and 6b closes an electrical circuit between the conductors 8 and 9'.

In each contact device 4 and 4', the lower end of the upper reed element 6a or 6a and the upper end of the corresponding lower reed element 6!) or 6b is positioned under the control of the magnetic field of the corresponding electromagnet 1, 2, 2', 3, 3. Thus, the lower end of the upper reed element 6a or 6a makes electrical contact with the upper end of the corresponding lower reed element 6b or 6b, to close an electrical circuit, under the control of the magnetic field produced by the corresponding electromagnet, and breaks electrical contact with said upper end of said corresponding lower reed element, to open the electrical circuit, under the control of said magnetic field.

The electromagnetic switch matrix of the present invention is supported by a magnetic shunt plate 11 (FIGS. 1, 2, 3, 5, 6, 7, 8, 9 and 10). The magnetic shunt plate 11 comprises a substantially planar plate of magnetic material or a substantially planar plate of non-magnetic material having magnetic material on its opposite planar surfaces. The magnetic material may comprise coatings, layers or sheets afiixed to the opposite planar surfaces of the non-magnetic material. A plurality of holes are formed through the magnetic shunt plate 11 in groups of three.

The core 1 of each electromagnet is supported in the center hole of 'each group of three at its central area, so that the upper inner and outer coils 2 and 3 end at and abut the upper surface of the magnetic shunt plate 11 and the lower inner and outer coils 2' and 3 end at and abut the lower surface of said magnetic shunt plate. An equal axial length of each core 1 extends above and below the magnetic shunt plate 11. Each core 1 is firmly atfxed to the magnetic shunt plate 11 and the coils 2, 2', 3 and 3' of each electromagnet are electrically insulated from said magnetic shunt plate by a pair of washers 12 and 12' (FIGS. 3, 6, 7 and 10) of electrically insulating material coaxially positioned on said core between the upper coils 2 and 3 and said magnetic shunt plate and between the lower coils 2' and 3' and said magnetic shunt plate.

The remaining two holes 13 and 13' of each group of three holes (FIGS. 2 and 3) are spaced from the center hole, and the contact devices 4 and 4 are positioned in said holes and passing through them. Thus, the contact device 4 passes through the hole 13 and does not contact the magnetic shunt plate 11 and the contact device 4' passes through the hole 13' and does not contact said magnet shunt plat-e. An equal axial length of each contact device 4 and 4' extends above and below the magnetic shunt plate 11.

The assembly of the electromagnetic switch matrix of FIG. 1 by the electrical connection of the electromagnetic switches is shown in FIG. 4. Assuming that there are 8 by 8 or 64 electromagnetic switches, as indicated in FIG. 4, each of said electromagnetic switches is indicated by a small circle in said figure. If, for example, the electro magnetic switch X7, Y0 is selected by suitable excitation of its coils, only the contact devices of said electromagnetic switch, at the intersection 14 (FIG. 4) will be operated to close their corresponding circuits, as shown in and described with reference to FIG. 9. The other electromagnetic switches of the matrix, at the intersections X0, Y0, X1, Y0, X2, Y0 X6, Y0, X7, Y1, X7, Y2 X7, Y7, and so on, are deenergized, so that their corresponding circuits are open, as shown in and described with reference to FIG. 8. I

In manufacturing the electromagnetic switch matrix of the present invention and electrically connecting and winding the coil of the electromagnets thereof, the cores 1 are first firmly affixed in the magnet shunt plate 11 in the aforedescribed manner (FIGS. 6 and 7). The upper inner and lower inner coils 2 and 2' then continuously wound to provide the matrix arrangement of FIG. 4 in a manner, in FIGS. 6 and 7, whereby there are 16 coil windin-g ends. If the coils were wound separately, there would be 256 individual coils, since each of the 64 electromagnets of the matrix comprises 4 coils.

The coils in the X rows are continuously wound 19 turns, for example, around each core 1 in its portion above the magnetic shunt plate 11, as shown in FIG. 6, and 39 turns, for example, around each core in its portion below said magnetic shunt plate. The ends of the windings of each of the X rows of coils above and below the plate 11 are connected in series. The coils in the Y columns are continuously wound 39 turns, for example, around each core 1 in its portion above the magnetic shunt plate 11, as shown in FIG. 7 and 19 turns, for example, around each core in its portion below said magnetic shunt plate. The ends of the windings of each of the Y columns of coils above and below the plate 11 are connected in series.

The inner upper coils 2 and the inner lower coils 2' (FIGS. 1, 2., 5, 8, 9 and 10) are connected in the Y columns of FIG. 4 and the outer upper coils 3 and the outer lower coils 3' are connected in the X rows of FIG. 4. When either the upper and lower inner coils 2 and 2 or the upper and lower outer coils 3 and 3' are energized or excited, either the Y or the X coils (FIG. 4) are energized and the corresponding contact devices are open or disconnected (FIG. 8). When both the upper and lower inner coils 2 and 2' and the upper and lower outer coils 3 and 3' are energized or excited simultaneously, however, the Y and the X coils are simultaneously energized and the corresponding contact devices are closed or connected (FIG. 9).

As shown in FIG. 8, when either the upper and lower inner coils 2 and 2 or the upper and lower outer coils 3 and 3 are energized, the core 1 is magnetized with an N pole at its upper end, S poles at its center portion at the magnetic shunt plate 11 and a N pole at its lower end. These polarities may be reversed, of course, dependent upon the direction of the windings of the coils, to an S pole at each of the upper and lower ends and an N pole at its center. When the upper or lower coils magneize the core 1 as shown in FIG. 8, they magnetize the reed elements of the contact devices 4 and 4 .in a manner whereby the upper end of the upper reed elements 6a and 6a of each of said contact devices, respectively, is magnetized with an S pole, the lower end of each of said upper reed elements is magnetized with an N pole, the upper end of each of the lower reed elements 6b and 6' is magnetized with an N pole and the lower end of each of said lower reed elements is magnetized with an S pole. The polarities of the reed elements 611, 6a, 6b and 6b are reversed, if those of the core 1 are reversed.

The upper and lower inner or outer coils are energized for a period of time sufficient to magnetize the core and reed elements in the aforedescribed manner. If the period of energization is sufficient to magnetize the core 1, but

insufficient to magnetize the reed elements 6a, 6a, 6b, 6b, the residual magnetism of said core is sufiicient to magnetize said reed elements in the manner shown in FIG. 8. When the magnetic polarities are as shown in FIG. 8, the upper and lower reed elements 6a and 6b repel each other, since they have the same polarity at their adjacent ends, and the upper and lower reed elements 6a and 6b repel each other, since they have the same polarity at their adjacent ends. Since their reed elements are repelled, the contact devices 4 and 4' maintain open circuits. The magnetic shunt plate 11 functions as part of the magnetic circuit.

As shown in FIG. 9, when all of the upper and lower inner coils 2 and 2 and the upper and lower outer coils 3 and 3 are energized simultaneously, the core 1 is magnetized with an N pole at its upper end, an S pole at its center portion at the upper surface of the magnetic shunt plate 11, an N pole at its center portion at the lower surface of said magnetic shunt plate and an S pole at the lower end of the core. These polarities may be reversed, dependent upon the direction of the windings of the coils, to the opposite polarities. When the upper and lower coils magnetize the core 1 as shown in FIG. 9, they magnetize the reed elements of the contact devices 4 and 4 in a manner whereby the upper end of the upper reed element 6a and 6a of each of said contact devices, respectively, is magnetized with an S pole, the lower end of each of said upper reed elements is magnetized with an N pole, the upper end of each of the lower reed elements 6b and 6b is magnetized with an S pole and the lower end of each of said reed elements is magnetized with an N pole. The polarities of the reed elements 6a, 6a 6b and 6b are reversed, if those of the core 1 are reversed.

When the magnetic polarities are as shown in FIG. 9, the upper andlower reed elements 6a and 6b attract each other, since they have the opposite polarity at their adjacent ends, and the upper and lower reed elements 6a and 6b attract each other, since they have the opposite polarities at their adjacent ends. Since their reed elements are attracted, the contact devices 4 and 4' maintain closed circuits. Even if the period of energization of the upper and lower inner and outer coils is insufficient to magnetize the reed elements 611, 6a, 6b and 6b, the residual magnetism of the core 1 is sufficient to magnetize said reed elements in the manner shown in FIG. 9. The magnetic shunt plate 11 does not function as part of the magnetic circuit to any appreciable extent in the condition illustrated in FIG. 9.

The magnetization conditions in FIGS. 8 and 9 differ from each other, since the directions of magnetization of the core 1 in the magnetization condition of FIG. 8 are different from those of the core 1 in the magnetization condition of FIG. 9. More specifically, the portion of the core 1 extending below the magnetic shunt plate 11 is magnetized in different directions in the magnetization conditions of FIGS. 8 and 9. When the electromagnetic switch is in its magnetization condition of FIG. 9, so that the circuits are closed by the reed elements of each of the contact devices 4 and 4, said switch may be opened or switched to its magnetization condition of FIG. 8 by deenergizing either the inner coils 2 and 2' or the outer coils 3 and 3'.

As shown in FIG. 10, the upper inner and outer coils 2 and 3 are wound on the core 1 on one side of the magnetic shunt plate 11 and the lower inner and outer coils 2 and 3' are wound on said core on the other side of said magnetic shunt plate. The direction of magnetization of the core 1 may be inverted or reversed by varying the winding direction of the inner and outer coils. The residual magnetism of the core 1 controls the opening and closing of the reed elements of the contact devices 4 and 4' (not shown in FIG. 10, but shown in FIGS. 8 and 9).

As shown in FIG. 10, the coils 2, 2', 3 and 3 are wound differentially, so that when current is supplied to only one of the X coils or Y coils, the portions of the core 1 on opposite sides of the magnetic shunt plate 11 are magnetized in opposite directions (FIG. 8) and the free ends of the reed elements of the contact devices 4 and 4 repel each other .to open the circuits of such reed elements. When both the X and Y coils are simultaneously supplied with current, however, the portions of the core 1 on opposite sides of the magnetic shunt plate 11 are magnetized in the same direction (FIG. 9) and the free ends of the reed elements of the contact devices 4 and 4' attract each other to close the circuits of such reed elements.

The placement pattern of electromagnetic switches for the electromagnetic switch matrix of the present invention is completely different from that of the electromagnetic switch matrix of the prior art. FIG. 11 is an electromagnetic switch matrix of planar grid configuration of the prior art. The electromagnetic switches utilized in the matrix of FIG. 11 are Ferreed units, as hereinbefore mentioned. In FIG. 11, there are 8 by 8, or 64 electromagnetic switches, each indicated by a small rectangle. Each of the electromagnetic switches comprises a pair of cores, two sealed contact devices positioned on either side of the cores in operative proximity with the cores and X and Y coils wound on the cores in the aforedescribed manner. The electromagnetic switches of the prior art matrix of FIG. 11 are so positioned that in each of said switches, the axes of the cores and the flanking contact devices are coplanarly positioned in a common plane perpendicular to the magnetic shunt plate, as hereinbefore described. The common planes of the electromagnetic switches of the prior art matrix are parallel to each other and each is at a positive slope of approximately 45 with the X and Y axes.

If, for example, it is desired to operate the contact devices of the electromagnetic switch at the intersection of the X4 row and the Y2 column, if current is supplied to the X4 and Y2 coils, both said X4 coils and said Y2 coils are energized in said electromagnetic switch. This closes the circuit contacts of the reed elements of the contact devices of the electromagnetic switch X4, Y2.

8 At every other X4 and Y2 intersection, only one of the X and Y coils is energized, so that the circuit contacts of the reed elements of the corresponding contact devices are opened. Thus, the contacts of the electromagnetic switches at the intersections X4, Y0, X4, Y1, X4, Y3, X4, Y4, X4, Y5, X4, Y6, X4, Y7, X0, Y2, X1, Y2, X2, Y2, X3, Y2, X5, Y2, X6, Y2, and X7, Y2 are opened.

As described, in selecting an electromagnetic switch of the matrix for operation, not only the selected switch is energized, but switches which are not selected are energized due to energization of the selected switch. Thus, if the switch X4, Y2 is selected and energized, the adjacent switches X3, Y1, X3, Y3, X5, Y1 and X5, Y3 are affected by the current flowing in the X4, Y2 coils, although the non-selected switches themselves are not energized. Conversely, since the residual magnetism of the cores maintains the non-operating or open condition of the nonselected electromagnetic switches, the leakage flux of the residual magnetism of the cores affects the operation of the selected electromagnetic switch X4, Y2.

In the matrix arrangement of the prior art, therefore, the selected electromagnetic switch and the non-selected electromagnetic switches which are adjacent the selected switch, but not in the same row or column, interfere with each other magnetically. The magnetic interference between selected and non-selected adjacent switches in the matrix of the prior art decreases the stability of operation of the contact devices and causes erroneous operation of the contact devices. The degree of magnetic interference in the prior-art matrix arrangement of FIG. 11, is determined by the strength of the magnetic field produced by the mutual leakage flux of the selected switch X4, Y2 and the non-selected switches X3, Y1, X3, Y3, X5, Y1 and X5, Y3.

The aforescribed mutual interference between the selected and non-selected switches may be decreased by increasing the space or distances between switches or by decreasing the surfaces of the switches which face each other. In accordance with the present invention, the electromagnetic switches of the matrix are positioned in a determined pattern which minimizes the mutual interference by decreasing the surfaces of the switches which face each other. The electromagnetic switch matrix of the present invention is shown in one embodiment in FIGS. 1 and 12.

In the embodiment of FIGS. 1 and 12, the common planes of the electromagnetic switches, passing through the axes of the core and the flanking contact devices of each switch and perpendicular to the magnetic shunt plate, are at right angles to each other in the adjacent Y columns. Thus, in FIG. 12, in the odd-numbered Y columns, the common planes of the switches, represented by small rectangles, are parallel to each other and each is at a negative slope of approximately 45 with the X and Y axes. In FIG, 12, in the even-numbered Y columns, the common planes of the switches are parallel to each other and each is at a positive slope of approximately 45 with the X and Y axes. The same effect as the pattern of FIG. 12 may be obtained if the switches of the X rows, rather than the Y columns, are positioned with the common planes of adjacent X rows at right angles to each other.

In the prior art matrix arrangement of FIG. 11, the contact devices of the selected electromagnetic switch X4, Y2 and the non-selected adjacent switches X3, Y3 and X5, Y1 are positioned with their common planes in parallel with each other and with the common planes of said selected switch and the non-selected adjacent switches X3, Y1 and X5, Y3 in coplanar relation. This matrix arrangement thus provides maximum surfaces of the switches which face each other, so that the mutual. interference between switches is a maximum.

In the matrix arrangement of the present invention of FIGS. 1 and 12, the common planes of the selected electromagnetic switch X4, Y2 and the non-selected adjacent switches X3, Y3 and X5, Y1, as well as X3, Y1 and X5, Y3 are positioned at right angles to each other. The matrix arrangement of the present invention thus provides minimum surfaces of the switches which face each other, so that the mutual interference between switches is considerably decreased and stable operation is attained.

In a known electromagnetic switch such as, for example, the Ferreed switch hereinbefore mentioned, there are two cores in which the magnetization may be inverted. In the electromagnetic switch of the present invention, the inner upper and lower coils 2 and 2' and the outer upper and lower coils 3 and 3' are wound on a single core 1, with or without an intervening layer of electrical insulation. There is very little wasted space in the electromagnetic switch of the present invention and such switch has a high efiiciency in excitation of the core 1 by the coils 2, 2, 3 and 3'. The effective length of the coils of the switch of the present invention may be reduced; the length of a coil of the switch of the present invention required to provide a magnetomotive force of a determined magnitude being less than 30% of the length of the coil of the Ferreed switch required to provide the same magnetomotive force. This permits coils of reduced amounts of copper to be used in the electromagnetic switch of the present invention and the electrical power or energy required to energize such coils is considerably reduced in proportion to the reduction of the coil length.

In the Ferreed switch, an independent space of approximately 5 mm. is required, in addition to the space required by the contact devices and the X and Y coils, for the winding tool. In the electromagnetic switch of the present invention, the cores 1 (FIG. 3) are first provided and the coils are then wound in accordance with FIGS. 6 and 7. The electromagnets each are completed as shown in FIGS. 1 and 2. It is thus evident, that in the electromagnetic switch of the present invention, the spaced occupied by the contact devices 4 and 4' is effectively utilized for the winding of the coils. After completion of the winding of the coils, the contact devices 4 and 4' are positioned in the holes 13 and 13', respectively (FIGS. 2 and 3) of the magnetic shunt plate 11.

The central portions of the yokes 5 and 5' of the electromagnetic switch of the present invention (FIGS. 1 and 5) are maintained in contact with the upper and lower ends, respectively, of the core 1 and the end portions of said yokes are maintained magnetically coupled with the reed elements of the contact devices 4 and 4 via tongue-shaped portions of said yokes at small magnetic reluctance in order to provide a magnetic circuit for the magnetic flux from said core to said respective contact devices. The yokes 5 and 5' are electrically insulated from the reed elements of the contact devices 4 and 4'. The yokes Sand 5 improve the efficiency of the X and Y coils, reduce magnetic losses and reduce leakage of the magnetic flux required for switch operation.

The positioning pattern of the electromagnetic switches of the electromagnetic switch matrix of the present invention (FIGS. 1 and 12) considerably reduces induction in adjacent coils and considerably reduces noise. In an electromagnetic switch of the prior art such as, for example, in the Ferreed switch, a pair of plate-shaped cores are utilized and the combined volume of the pair of cores is greater than that of the rod-shaped core 1 of the electromagnet of the present invention.

The magnetic shunt plate of the electromagnetic switch of the prior art is a thick and heavy weight plate, whereas the magnetic shunt plate of the electromagnetic switch of the present invention may be made thin and light weight by the elimination of part thereof or the replace ment of part thereof with material of lighter weight. Thus, the magnetic shunt plate of the electromagnetic switch of the present invention may comprise a plate of aluminum alloy having a soft magnetic material on both planar surfaces thereof, or a plastic, such as, for example, a synthetic resin, plate having a soft magnetic material on both planar surfaces thereof. If an increase in weight is permissible, the cost of the magnetic shunt plate is decreased if an iron plate is utilized as said magnetic shunt plate.

In an electromagnetic switch of the prior art such as, for example, a Ferreed switch, noise is produced and contact chattering of the reed elements of the contact devices occurs during unsuitable energization or excitation periods of the coils. This is caused by the supply of a current of large magnitude to the X and Y coils and the continuous production of a magnetic field by the coils and by the cores which is contrary in direction to the magnetic field produced by the coils for magnetizing the contact devices.

In the electromagnetic switch of the present invention, the direction of the magnetic field, produced for magnetizing the contact devices by the supply of current to the coils, is not always contrary in direction to the magnetic field produced by the residual magnetism of the core 1. That is, the directions of the magnetic fields vary in accordance with the condition of operation of the switch, as shown in FIGS. 8 and 9. Thus, when the coils are energized for a long period of time, there is no limitation on the operation of the contact devices and the magnetic field produced by the magnetomotive force of the coils may abet the residual magnetic field of the core. This reduces erroneous operation, noise and contact chattering. Furthermore, the handling of the switches is facilitated and the margin of operation is increased. Since, in the electromagnetic switch of the present invention, the direction of the magnetic field produced by the core is the same as that of the magnetic field produced by the energization of the X and Y coils for the magnetization of the contact devices, noises evident in the Ferreed switch are minimized in the switch of the present invention. Furthermore, the same direction of the magnetic fields permits a reduction of the electrical power required to energize the coils and permits simplification of the magnetic circuit of the switch of the present invention.

The volume occupied by the electromagnetic switch matrix of the present invention is about one third that of the electromagnetic switch matrix of the prior art which utilizes 64 Ferreed switches, as hereinbefore mentioned. Furthermore, the weight of the electromagnetic switch matrix of the present invention is two fifths that of the prior art electromagnetic switch matrix and the electrical power consumed by the electromagnetic switch matrix of the present invention is one third that of the electromagnetic switch matrix of the prior art.

Various types of voice line elements are utilized for time and space division electronic exchanges. The voice line element must be small in size, light in weight, of high reliability and of low cost, and must operate at a high speed and consume little electrical power. The principal requirements are the small size and light weight requirements, since the voice line element occupies a large space in the electronic exchange. Thus, the size of the electronic exchange may be considerably reduced if the size of the voice line element is reduced. As hereinbefore mentioned, the electromagnetic switch matrix of the present invention is considerably smaller in size and lighter in weight than the electromagnetic switch matrix of the prior art and consumes less electrical power than the electromagnetic switch matrix of the prior art, and is therefore, especially suitable for use as the voice line element of an electronic exchange.

While the invention has been described by means of specific examples and in a specific embodiment, we do not wish to be limited thereto, for obvious modifications will occur to those skilled in the art without departing from the spirit and scope of the invention.

We claim:

1. An electromagnetic switch matrix, comprising a magnetic shunt plate and a plurality of electromagnetic switches each comprising a rod-like core of magnetic material extending through and positioned in said magnetic shunt plate substantially perpendicularly to said magnetic shunt plate and for a substantially equal length on each side of said shunt plate, said core having an axis extending substantially perpendicularly to said shunt plate, energizing coil means coaxially wound on said core on each side of said shunt plate for providing a magnetic field, sealed contact means extending through and positioned in said magnetic shunt plate substantially perpendicularly to said magnetic shunt plate and for a substantially equal length on each side of said shunt plate, said sealed contact means comprising at least a single substantially elongated housing positioned in operative proximity with said core and having an axis extending substantially perpendicularly to said magnetic shunt plate, the axis of said core and the axis of the housing of said sealed contact means forming a common plane, said plurality of electromagnetic switches being positioned in said shunt plate in spaced relation to each other in columns and rows in a manner whereby the common planes of the electromagnetic switches of one of a row and column of said switches are parallel to each other and are substantially perpendicular to the common planes of the switches of the next adjacent one of a row and collumn of said switches and the electromagnetic switches of the other of a row and column of said switches are perpendicular to each other and at an angle of 45 with said other of said row and column.

2. An electromagnetic switch matrix as claimed in claim 1, wherein the sealed contact means of each of said electromagnetic switches comprises a pair of substantially elongated housings positioned in operative proximity with said core on either side thereof and each having an axis extending substantially perpendicularly to said magnetic shunt plate, the axis of said core and the axes of the housings of said sealed contact means forming a common plane.

3. An electromagnetic switch matrix as claimed in claim 1, wherein the housing of the sealed contact means of each of said electromagnetic switches houses a pair of magnetizable reed elements each passing through and ex tending from an opposite end of said housing, having free ends adjacent each other in the central area of said housing and having outer terminals for connection to electrical conductors, said coil means when energized providing a magnetic field of a determined direction in the central area of said housing and the residual magnetism of said core providing a magnetic field of the same direction in said central area of said housing for magnetizing the free ends of the reed elements of said sealed contact means in a predetermined manner dependent upon the total energization of said coil means.

4. An electromagnetic switch matrix as claimed in claim 1, wherein the coil means of each of said electromagnetic switches comprises an upper inner coil coaxially wound on said core on one side of said shunt plate, an upper outer coil coaxially wound on said upper inner coil, a lower inner coil coaxially Wound on said core on the other side of said shunt plate and a lower outer coil coaxially wound on said lower inner coil.

5. An electromagnetic switch matrix as claimed in claim 2, wherein each of said electromagnetic switches further comprises a magnetic yoke coupled to one end of said core and to the corresponding ends of the housing of each of said sealed contact means and another magnetic yoke coupled to the other end of said core and to the corresponding ends of the housing of each of said sealed contact means.

'6. An electromagnetic switch matrix as claimed in claim 2, wherein the housing of each of the sealed contact means of said electromagnetic switches houses a pair of magnetizable reed elements each passing through and extending from an opposite end of the housing, having free ends adjacent each other in the central area of said housing and having outer terminals for connection to electrical conductors, said coil means when energized provid ing a magnetic field of a determined direction in the central area of each of said housings and the residual magnetism of said core providing a magnetic field of the same direction in said central area of each of said housings for magnetizing the free ends of the reed elements of each of said housings in a predetermined manner dependent upon the total energization of said coil means.

7. An electromagnetic switch matrix as claimed in claim 6, wherein the coil means of each of said electromagnetic switches comprises an upper inner coil coaxially wound on said core on one side of said shunt plate, an upper outer coil coaxially wound on said upper inner coil, a lower inner coil coaxially wound on said core on the other side of said shunt plate and a lower outer coil coaxially wound on said lower inner coil.

8. An electromagnetic switch matrix as claimed in claim 7, wherein the common planes of the electromagnetic switches of alternate ones of one of a row and column of said switches are parallel to each other and the common planes of the electromagnetic switches of the alternate others of said one of a row and column of said switches are parallel to each other, and said common planes of said alternate ones of said switches and said common planes of said alternate others of said switches are substantially perpendicular to each other.

9. An electromagnetic switch matrix as claimed in claim 1, wherein said plurality of electromagnetic switches is positioned in said shunt plate in spaced relation to each other in columns and rows in a manner whereby the common planes of the electromagnetic switches of each column are parallel to each other and are substantially perpendicular to the common planes of the switches of the next adjacent column of said switches and the common planes of adjacent ones of the electromagnetic switches of each row are perpendicular to each other and t an angle of 45 with the row.

10. An electromagnetic switch matrix as claimed in claim 1, wherein said plurality of electromagnetic switches is positioned in said shunt plate in spaced relation to each other in columns and rows in a manner whereby the common planes of the electromagnetic switches of each row are parallel to each other and are substantially perpendicular to the common planes of the switches of the next adjacent row of said switches and the common planes of adjacent ones of the electromagnetic switches of each column are perpendicular to each other and at an angle of 45 with the column.

11. An electromagnetic switch matrix, comprising a magnetic shunt plate and a plurality of electromagnetic switches each comprising a core of magnetic material extending through said shunt plate substantially perpendicularly thereto, energizing coil means wound on said core on each side of said shunt plate and contact means extending through said shunt plate substantially perpendicularly thereto, said core and said contact means forming a common plane, said plurality of electromagnetic switches being positioned in said shunt plate in spaced relation to each other in columns and rows in a manner whereby the com-mon planes of the electromagnetic switches of one of a row and column of said switches are parallel to each other and are substantially perpendicular to the common planes of the switches of the next adjacent one of a row and column of said switches and the electromagnetic switches of the other of a row and column of said switches are perpendicular to each other and at an angle of 45 with said other of said row and column.

12. An electromagnetic switch matrix as claimed in claim 11, wherein said plurality of electromagnetic switches is positioned in said shunt plate in spaced relation to each other in columns and rows in a manner whereby the common planes of the electromagnetic switches of. each column are parallel to each other and are substantially perpendicular to the common planes of the switches of the next adjacent column of said switches and the common planes of adjacent ones of the electromagnetic switches of each row are perpendicular to each other and at an angle of 45 with the row.

13. An electromagnetic switch matrix as claimed in claim 11, wherein said plurality of electromagnetic switches is positioned in said shunt plate in spaced relation to each other in columns and rows in a manner whereby the common planes of the electromagnetic switches of each row are parallel to each other and are substantially perpendicular to the common planes of the switches of the next adjacent row of said switches and the common planes of adjacent ones of the electromagnetic switches of each column are perpendicular to each other and at an angle 15 of 45 with the column.

1 4 References Cited UNITED STATES PATENTS 3,293,578 12/1966 Else 335-152 OTHER REFERENCES IBM Technical Disclosure Bulletin, vol 3, No. 10, March 1961 (pages 105-106).

IBM Technical Disclosure Bulletin, vol. 6, No. 4, September 1963 (pages 55-56). 1963 (pages 55-56).

Bell Laboratories Record, vol. 42, 1964; Authors-Feiner and Peek (pages 71-75).

BERNARD A. GILHEANY, Primary Examiner. H. BROOME, Assistant Examiner. 

